There are an increasing number of people globally for whom transitions from a bed or chair subject them to a risk of accidental harm. For example, the elderly, those suffering from debilitating diseases, and those suffering from dementia (including Alzheimer's dementia) as well as other mental and medical conditions are at risk when transitioning from a sitting or lying position. For example, for the elderly and/or infirm, accidents and injuries may occur as a result of wandering out of a bed or chair. However, the need for constant vigilance may cause significant stress to caregivers in home, hospitals and nursing facilities. It would be beneficial to provide methods and systems for detection and alerting of bed and/or chair leaving events, which could not only enhance the safety of subjects but also alleviate the stress of their caregivers. Further, it would also be beneficial to provide one or more methods and apparatuses for detecting and alerting caregivers of such transitions to prevent illness/accidents by remotely monitoring subject's routine activities without requiring the use of cameras due to privacy concerns.
Previous systems for monitoring subjects to prevent falls or wandering typically require more complex, and therefore expensive, methods to track subject movement. For example, Japanese Laid-Open Patent Application No. 2-280733 describes the use of load sensors installed on a subject's bed to detect his or her bed departure, and uses weight information to determine whether a user is still on the bed or has left the bed. Similarly, Japanese Patent No. 3093745, Japanese Patent No. 3322632, and U.S. Pat. No. 5,276,432 each describe the calculation of a subject's center of gravity from weight information of four points on a bed and use the center-of-gravity position information to monitor the movement of a user in bed. U.S. Pat. No. 6,239,706 disclosed describes an in-bed state determination based on measured load characteristics. These references, and similar techniques, all require specialized beds installed with load sensors (or retrofitted beds). The associated costs and cumbersome set-up prevent their wide applications in homes as well as in nursing facilities and hospitals.
As another solution, U.S. Pat. No. 8,736,439 uses a sensor sock to detect an individual leaving the bed by detecting a change in foot pressure. However, not all patients are comfortable wearing socks (especially when sleeping).
Alternatively, U.S. Pat. No. 6,307,481, U.S. Pat. No. 6,501,386, U.S. Pat. No. 6,661,347, U.S. Pat. No. 6,703,939, U.S. Pat. No. 6,864,796, U.S. Pat. No. 7,095,331, U.S. Pat. No. 7,145,461, and U.S. Pat. No. 7,479,890 describe systems to evaluate movement of a body relative to an environment by sensing dynamic and static accelerative phenomena, and determines whether the evaluated body movement is within an environmental tolerance. Unfortunately assumptions typically made by such systems about the patient's environment may not be accurate, or may lead to artifacts. In addition, such systems may be expensive and difficult to operate.
Finally, U.S. Pat. No. 8,814,811 describes a fall detection algorithm based on both the dynamic acceleration and static position signals and the high sampling rate required for acquiring the dynamic signal consumes energy.
Described herein are methods and apparatuses that may address the issues discussed above. For example, described herein are methods and apparatuses that may detect and notify caregivers that a patient being monitored (a subject) has changed body position in a manner that corresponds specifically with getting out of a bed or getting out of a chair. These apparatuses and methods are simple, relatively low-cost and easy to implement.